- Thread starter
- #21
Do you think its the idle solenoid or poor job on the carb rebuild? Landcrusher offered up a free solenoid, I might take him up on that.
need help adjusting carb (1 Viewer)
- Thread starter liko
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
- Thread starter
- #23
Sorry, its been a while
Solenoid works fine.....I think.
The nozzle in the primary was clogged, so I took carb apart and cleaned that with a small wire then carb cleaner and then air.
Pulled the choke then started it up and idled a little on the high side (no tach attached).
Gave it some gas without any hesitation or sputtering, hopefully solved that problem.
Attached vacuum gauge- 15 inches
Attached tachometer- 1100 rpm
Idle screw only went up higher. So I turned it back where it was.
Loosened dizzy and turned it till it slowed down to 800, then it backfired once at 700 and couple more times at 650, so I went back up to 800.
Vacuum now at 13 inches.
Died.
Won't start.
Look inside carb, Secondary flooding? Idle circuit? how do I clean the idle circuit.
Any and all help greatly appreciated.
Solenoid works fine.....I think.
The nozzle in the primary was clogged, so I took carb apart and cleaned that with a small wire then carb cleaner and then air.
Pulled the choke then started it up and idled a little on the high side (no tach attached).
Gave it some gas without any hesitation or sputtering, hopefully solved that problem.
Attached vacuum gauge- 15 inches
Attached tachometer- 1100 rpm
Idle screw only went up higher. So I turned it back where it was.
Loosened dizzy and turned it till it slowed down to 800, then it backfired once at 700 and couple more times at 650, so I went back up to 800.
Vacuum now at 13 inches.
Died.
Won't start.
Look inside carb, Secondary flooding? Idle circuit? how do I clean the idle circuit.
Any and all help greatly appreciated.
- Thread starter
- #24
I did try removing the solenoid and spraying cleaner and air through that hole, seemed okay. Removed the idle mixture screw and sprayed cleaner and then air through that. Prior to my post above. Thanks pin head
Don't screw with the distributor yet. You need it to get to idle at 650 to set the timing properly. If the idle speed screw won't get it to idle that low, then something is hanging up the linkage and preventing the throttle plate from closing completely.
^ditto. Did you push the choke back in before you adjusted the idle? If not, the fast idle speed screw will override the (normal) idle speed screw. Put the dizzy back where it was, warm it up, push in the choke, then use the idle speed screw to get it to 650ish, then adjust the idle mixture, reset the idle speed screw to 650, THEN adjust the timing to the proper setting.
- Thread starter
- #27
I went back and re-torqued the manifold bolts, thinking there was a vacuum leak. Two bolts turned a little, less than a quarter turn.
I pulled the choke knob out all the way, and fired up the F engine. Idled smooth at high RPM's. Warmed up for one minute (its hot here 90 deg outside), then pushed in the choke knob all the way. Still idling smoothly.
Connected the tach- 750 RPM
Connected vacuum gauge- 16-17 inches
Adjusted idle speed screw down to 650 RPM, vacuum still at 16-17 inches.
Adjusted idle mixture screw to no effect, all the way out or all the way in RPM does not change and vacuum does not change. I know there are two holes that the idle mixture screw connects to, I thought they were clear of any gunk but I guess I should take the carb off and confirm that, what a PITA.
Any other suggestions? Appreciate it
I pulled the choke knob out all the way, and fired up the F engine. Idled smooth at high RPM's. Warmed up for one minute (its hot here 90 deg outside), then pushed in the choke knob all the way. Still idling smoothly.
Connected the tach- 750 RPM
Connected vacuum gauge- 16-17 inches
Adjusted idle speed screw down to 650 RPM, vacuum still at 16-17 inches.
Adjusted idle mixture screw to no effect, all the way out or all the way in RPM does not change and vacuum does not change. I know there are two holes that the idle mixture screw connects to, I thought they were clear of any gunk but I guess I should take the carb off and confirm that, what a PITA.
Any other suggestions? Appreciate it
- Joined
- Apr 14, 2004
- Threads
- 1,450
- Messages
- 36,631
- Location
- 818-953-9230
- Website
- www.marksoffroad.net
liko said:
Try turning the idle speed down even more, just for now. Just a hunch.
- Thread starter
- #29
Okay, turned idle speed screw down to 600 RPM, still pulling 16 inches of vacuum
Turned idle mixture screw (facing valve cover) clockwise 1.5 turns idle went down to 400-450 ish
Turned idle mixture screw counter clockwise 3 full turns RPM at 650
Unsure how to progress.........
Turned idle mixture screw (facing valve cover) clockwise 1.5 turns idle went down to 400-450 ish
Turned idle mixture screw counter clockwise 3 full turns RPM at 650
Unsure how to progress.........
A few posts ago, you turned the idle speed down by adjusting the timing. Did you put it back?
I think that where Mark is going with this is you could have the idle speed screw in so far that you're not using the idle circuit on the carb anymore.
Now that you've got it "idling" at 650, I'd adjust the timing to spec and I'm guessing that that the RPM's will go up.
If so, adjust the idle speed screw back to keep it at 650 and adjust the timing again.
Once you have the idle at 650 and the timing at spec, the idle mixture screw should behave normally.
I think that where Mark is going with this is you could have the idle speed screw in so far that you're not using the idle circuit on the carb anymore.
Now that you've got it "idling" at 650, I'd adjust the timing to spec and I'm guessing that that the RPM's will go up.
If so, adjust the idle speed screw back to keep it at 650 and adjust the timing again.
Once you have the idle at 650 and the timing at spec, the idle mixture screw should behave normally.
- Thread starter
- #31
I think the FSM is confusing the hell outta me.......
"Turn the throttle valve adjusting screw in or out until the engine operates smoothly without stalling at lowest possible revolutions"
"Turn the idle adjusting screw to obtain highest steady vacuum at idle speed"
"Turn the throttle valve adjusting screw and the idle adjusting screw alternately to obtain a steady and highest vacuum with smooth engine operation at idle speed"
I turned the idle speed screw down to 600 RPM
Adjusted idle mixture screw and watched vacuum at 3 full turns vacuum topped out at 17.5 inches
Turned idle speed screw up to 650 RPM but vacuum did not change so I left it at that.
Is that it? Now I gotta get a timing light to set the timing.
"Turn the throttle valve adjusting screw in or out until the engine operates smoothly without stalling at lowest possible revolutions"
"Turn the idle adjusting screw to obtain highest steady vacuum at idle speed"
"Turn the throttle valve adjusting screw and the idle adjusting screw alternately to obtain a steady and highest vacuum with smooth engine operation at idle speed"
I turned the idle speed screw down to 600 RPM
Adjusted idle mixture screw and watched vacuum at 3 full turns vacuum topped out at 17.5 inches
Turned idle speed screw up to 650 RPM but vacuum did not change so I left it at that.
Is that it? Now I gotta get a timing light to set the timing.
- Thread starter
- #32
Sorry missed your post......
No timing light, was just timing by ear and the tach. I know, you can laugh yer asses off, but I was taking shots in the dark at that point. Ill advised I am sure.
Hopefully back on the right track now, is the timing light necessary?
No timing light, was just timing by ear and the tach. I know, you can laugh yer asses off, but I was taking shots in the dark at that point. Ill advised I am sure.
Hopefully back on the right track now, is the timing light necessary?
- Thread starter
- #33
Idling smoothly at 650. No hesitation or sputtering.
Fiddled with the dizzy, found that increasing RPM to 700 also increased vacuum to 19 inches.
Feel like I am getting farther away from baseline but its running good and many of the issues I started with have been fixed/ eliminated.
I know how you guys like pics so here you go......
Fiddled with the dizzy, found that increasing RPM to 700 also increased vacuum to 19 inches.
Feel like I am getting farther away from baseline but its running good and many of the issues I started with have been fixed/ eliminated.
I know how you guys like pics so here you go......
The deal is that there are three "knobs" that will change the rpm's-distributor timing, idle speed screw and idle mixture screw. And they are interdependent-(you can't properly adjust the timing unless the rpm's are right, and you can't adjust the idle mixture if the idle speed screw is in too far). You have to do things in the right order and repeat it until you get the right timing and the right rpm's.
Now that you are in the ballpark, you can do it right. Buy or borrow a timing light and set the timing. Once you've done that, the rpm's will have changed. Adjust the idle speed with the speed screw and recheck the timing. Repeat until the timing and rpm's are both right. Then adjust the idle mixture and if the rpm's have increased, use the idle speed screw to bring it back.
Now that you are in the ballpark, you can do it right. Buy or borrow a timing light and set the timing. Once you've done that, the rpm's will have changed. Adjust the idle speed with the speed screw and recheck the timing. Repeat until the timing and rpm's are both right. Then adjust the idle mixture and if the rpm's have increased, use the idle speed screw to bring it back.
- Thread starter
- #35
I borrowed a timing light from my boss, warmed up the engine, then adjusted timing till bb was on the pointer.
RPM at 800, adjusted with idle speed screw to 700, would not drop any more, high idle screw too high. Adjusted high idle screw down to 550, then used idle speed screw to bring RPM to 650.
Checked timing, bb off by a fraction, reset to dead on pointer.
RPM adjusted to 650, checked timing, all good.
Vacuum at 21 inches.
Going to adjust idle mixture now.
RPM at 800, adjusted with idle speed screw to 700, would not drop any more, high idle screw too high. Adjusted high idle screw down to 550, then used idle speed screw to bring RPM to 650.
Checked timing, bb off by a fraction, reset to dead on pointer.
RPM adjusted to 650, checked timing, all good.
Vacuum at 21 inches.
Going to adjust idle mixture now.
21" Hg at 650RPM is very good...
Some people, sometimes even myself, will time by vacuum gauge and not by timing light. Advance timing until best vacuum, then retard just a degree or two. Retard slightly more if you experience pre-ignition.
Some people, sometimes even myself, will time by vacuum gauge and not by timing light. Advance timing until best vacuum, then retard just a degree or two. Retard slightly more if you experience pre-ignition.
Last edited:
- Thread starter
- #37
I adjusted the idle mixture screw from 1.5 out, to 3.5 turns out, then back in a half. Took her for a cruise through the macadamia plantation, so much fun, topless, no doors, idling uphill in first. Nice to be able to drive her around, looking forward to doing the electrical work then get her street legal. Thanks to everyone for their help, I would be lost without you guys.
- Thread starter
- #38
Buy a star and show us...
- Thread starter
- #40
Done! Small price to pay
